Effect of Temperature on the Larval Development of <i>Blattella nipponica</i>（Blattaria: Blattellidae）

In recent years, the distribution area of Blattella nipponica has expanded northward in Japan. Since this species is a problematic nuisance and sanitary pest, the future expansion of their distribution should be predicted. Therefore, in this study, we investigated the influence of rearing temperature on the larval development. Significant arrested development was observed for this species at temperatures below 22°C, especially in the sixth-instar larvae. Arrested development was observed also at temperatures above 32°C, possibly due to high-temperature damage. Therefore, we calculate the developmental zero excluding data obtained at temperatures higher than 30°C. As a result, we could calculate the developmental zero and effective accumulated temperature for all instars, we estimated the environmental conditions in which this species can develop into an overwintering stage before the arrival of winter. The results suggested that the northern limit area of this species is Ibaraki Prefecture, but in fact this species has been found in Fukushima Prefecture. This may be because the Shimane population was used for this study. A more accurate estimate could be made by using a more northern population and by clarifying the life history of the northern population.